| ( | 40 | − | x | ) | ( | 500 | + | 2 | x | ) | − | 500 | = | 1950 |
| Left side of the equation = | 40 | ( | 500 | + | 2 | x | ) | − | x | ( | 500 | + | 2 | x | ) | − | 500 |
| = | 40 | × | 500 | + | 40 | × | 2 | x | − | x | ( | 500 | + | 2 | x | ) | − | 500 |
| = | 20000 | + | 80 | x | − | x | ( | 500 | + | 2 | x | ) | − | 500 |
| = | 19500 | + | 80 | x | − | x | ( | 500 | + | 2 | x | ) |
| = | 19500 | + | 80 | x | − | x | × | 500 | − | x | × | 2 | x |
| = | 19500 | − | 420 | x | − | x | × | 2 | x |
| 19500 | − | 420 | x | − | x | × | 2 | x | = | 1950 |